Isolate code better for unused options, config option to enable long
options, add some conditions to the tar tests in testsuite.
diff --git a/testsuite/tar/tar-handles-nested-exclude b/testsuite/tar/tar-handles-nested-exclude
index ad39506..39013a1 100644
--- a/testsuite/tar/tar-handles-nested-exclude
+++ b/testsuite/tar/tar-handles-nested-exclude
@@ -1,4 +1,5 @@
-# FEATURE: CONFIG_FEATURE_TAR_EXCLUDE
+# FEATURE: CONFIG_FEATURE_TAR_FROM
+# FEATURE: CONFIG_FEATURE_TAR_CREATE
 mkdir foo
 touch foo/bar
 tar cf foo.tar foo